His directions were recorded during a marathon phone session with investigators from his undisclosed prison.

It’s not the first time a company has created a product based on serial killers. There was the calendar:

And, the trading cards:

“Dark Minds” hosts John Kelly, a well-known criminal profiler, chose “13” for the show because he’d interviewed the killer several times before, producers said.

“We spoke to ’13’ over the phone for a couple of reasons,” says series executive producer Jeanie Vink. “Prison access is getting harder . . . and we just didn’t want to feed his ego on any level.”

“13,” who isn’t on death row — “There are some cases still pending and it’s possible he might be connected to more murders,” Vink says — was not paid to appear on the show.

Before Ted Bundy was executed in 1989, he tried to help authorities catch the Green River killer.

The show refuses to give any information on his identity, the murders he’s been convicted of or where he is being incarcerated. On the show, his voice is digitally altered so that it cannot be recognized.

Kelly and author/crime expert M. William Phelps, act as co-hosts for the show — set to debut in January.

The show takes up an unsolved murder case every week — including the “Eastbound Strangler” in Atlantic City, where four prostitutes were slain in 2006.

“The spooky part to me is how normal ’13’ sounds in real life,” says Vink. “We’re trying to get into his head and get his unique perspective.

“He certainly confirmed a lot of the suppositions that Kelly and the police are making as they built their profiles” of the killers, she says.